Topological crystalline insulator PbxSn1-xTe thin films on SrTiO3 (001) with tunable Fermi levels.

In this letter, we report a systematic study of topological crystalline insulator Pb_xSn_1-xTe (0 < x < 1) thin films grown by molecular beam epitaxy on SrTiO₃ (001). Two domains of Pb_xSn_1-xTe thin films with intersecting angle of α ≈ 45° were confirmed by reflection high energy diffraction, scanning tunneling microscopy, and angle-resolved photoemission spectroscopy (ARPES). ARPES study of Pb_xSn_1-xTe thin films demonstrated that the Fermi level of PbTe could be tuned by altering the temperature of substrate whereas SnTe cannot. An M-shaped valance band structure was observed only in SnTe but PbTe is in a topological trivial state with a large gap. In addition, co-evaporation of SnTe and PbTe results in an equivalent variation of Pb concentration as well as the Fermi level of Pb_xSn_1-xTe thin films. [ABSTRACT FROM AUTHOR]